401 research outputs found

    N=2 gauge theories and degenerate fields of Toda theory

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    We discuss the correspondence between degenerate fields of the W_N algebra and punctures of Gaiotto's description of the Seiberg-Witten curve of N=2 superconformal gauge theories. Namely, we find that the type of degenerate fields of the W_N algebra, with null states at level one, is classified by Young diagrams with N boxes, and that the singular behavior of the Seiberg-Witten curve near the puncture agrees with that of W_N generators. We also find how to translate mass parameters of the gauge theory to the momenta of the Toda theory.Comment: 23 pages,v2: minor corrections,published versio

    The Recent Overview and Prospects of Nuclear Power Policy and Industrial Strategies in the UK, Italy and Sweden

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    European countries that had moved away from nuclear energy or frozen the construction of new nuclear power plants have begun to return to the construction due to their pursuit of low-carbon electricity sources, energy security and requirements for replacements for existing nuclear plants. Particularly, we should pay attention to developments in the UK that vowed to launch the construction of new nuclear power plants in its 2007 Energy White Paper, and in Italy and Sweden that have begun to reconsider their legal ban on new nuclear plants. These countries launched nuclear power generation development comparatively in the early stage in the world, and built solid nuclear industry infrastructure, however after that, suspended the construction of new nuclear power plants for energy-related or economic reasons. In view of recent conditions, however, they are trying to reintroduce nuclear energy or expand nuclear energy use. Given these points, the three countries are viewed as symbols of Europes return to nuclear energy.nuclear energy, nuclear power, regulation, energy security, carbon emissions

    Patterns in evolutionary origins of heme, chlorophyll a and isopentenyl diphosphate biosynthetic pathways suggest non-photosynthetic periods prior to plastid replacements in dinoflagellates

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    BackgroundThe ancestral dinoflagellate most likely established a peridinin-containing plastid, which have been inherited in the extant photosynthetic descendants. However, kareniacean dinoflagellates and Lepidodinium species were known to bear “non-canonical” plastids lacking peridinin, which were established through haptophyte and green algal endosymbioses, respectively. For plastid function and maintenance, the aforementioned dinoflagellates were known to use nucleus-encoded proteins vertically inherited from the ancestral dinoflagellates (vertically inherited- or VI-type), and those acquired from non-dinoflagellate organisms (including the endosymbiont). These observations indicated that the proteomes of the non-canonical plastids derived from a haptophyte and a green alga were modified by “exogenous” genes acquired from non-dinoflagellate organisms. However, there was no systematic evaluation addressing how “exogenous” genes reshaped individual metabolic pathways localized in a non-canonical plastid.ResultsIn this study, we surveyed transcriptomic data from two kareniacean species (Karenia brevis and Karlodinium veneficum) and Lepidodinium chlorophorum, and identified proteins involved in three plastid metabolic pathways synthesizing chlorophyll a (Chl a), heme and isoprene. The origins of the individual proteins of our interest were investigated, and we assessed how the three pathways were modified before and after the algal endosymbioses, which gave rise to the current non-canonical plastids. We observed a clear difference in the contribution of VI-type proteins across the three pathways. In both Karenia/Karlodinium and Lepidodinium, we observed a substantial contribution of VI-type proteins to the isoprene and heme biosynthesises. In sharp contrast, VI-type protein was barely detected in the Chl a biosynthesis in the three dinoflagellates.DiscussionPioneering works hypothesized that the ancestral kareniacean species had lost the photosynthetic activity prior to haptophyte endosymbiosis. The absence of VI-type proteins in the Chl a biosynthetic pathway in Karenia or Karlodinium is in good agreement with the putative non-photosynthetic nature proposed for their ancestor. The dominance of proteins with haptophyte origin in the Karenia/Karlodinium pathway suggests that their ancestor rebuilt the particular pathway by genes acquired from the endosymbiont. Likewise, we here propose that the ancestral Lepidodinium likely experienced a non-photosynthetic period and discarded the entire Chl a biosynthetic pathway prior to the green algal endosymbiosis. Nevertheless, Lepidodinium rebuilt the pathway by genes transferred from phylogenetically diverse organisms, rather than the green algal endosymbiont. We explore the reasons why green algal genes were barely utilized to reconstruct the Lepidodinium pathway

    Cost-effectiveness Analysis of CO2 Reduction in the Automobile Sector

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    Various problems relating to energy and the environment clearly exist, such as global warming and a steep rise in the price fossil fuels, and resources. These problems should be addressed in the medium term or long run. As for the abatement of greenhouse gas emission, active discussions have been held on the stage of world politics to achieve the long-term goal. Although various approaches have been proposed by several research institutions and countries, sufficient studies have not yet been conducted on the roles of individual countries and sectors. Specifically, in the automotive transportation sector wherein oil demand and CO2 emissions are estimated to rise in the future with the marked progress of motorization in developing countries, it is increasingly important to study these subjects. We focused on the automotive transportation sector and studied the CO2 abatement potential and its cost performance in this sector. This article reports the results of the study.energy and the environment, Climate change, automotive transportation

    Current Status and Future Prospects of Electric Power as Automotive Fuel

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    The deployment of electric vehicles and plug-in hybrid vehicles on the premise of using low-carbon power sources (renewable energy and nuclear power) is expected to not only contribute to a stable energy supply by lowering dependence on oil (dependence on foreign supply sources) as fuel but also help to reduce CO2 emissions. Moreover, the use of night-time electricity is likely to help spread the use of electric vehicles for commuter use by reducing energy cost. However, it is important to remember that if conventional electricity, mainly generated by coal-fired power plants, is to be used as a power source, the deployment of electric vehicles and plug-in hybrid vehicles may not necessarily be effective in reducing CO2 emissions. It is also true that compared with vehicles powered by an internal-combustion engine, electric vehicles still have some shortcomings, such as their short driving range, some 100 km on a single charge of the battery, and the long battery-recharging time. To significantly increase the use of electric vehicles in the future, the key will be to develop a low-cost, high-performance battery. It will also be necessary to further reduce the cost of wind and photovoltaic power generation. As the use of electric vehicles spreads, it will become necessary to conduct a quantitative study on the optimization (cost minimization) of the power source mix (cost minimization), including additional power sources for automobiles.electric vehicles, optimization, power source
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